I had a home server on Wheezy (or, should I say, "stable". Wow, not gonna make that mistake again). I did a dist-upgrade before I'd read the release announcement and spent five minutes wondering why my home page no longer came up.
"What do you mean, 'Please upgrade your kernel before or while upgrading udev'? What do you mean, 'can't install linux-image-amd64', udev is broken'?" What the hell happened to my beautiful Wheezy -
- oh, crap, what do you mean, Jessie with systemd is the new stable ALREADY.
I also tried Pikoro's instructions above twice in a VM at work; *twice*, got the installer failing on me at the "Installing Software" step. And no hint as to what went wrong. So screw it, I thought. I'll install off the live image with all the defaults including that f'ed up systemd, rather than off the xfce-image.
"Oh, look. Broken a third time at the 'Installing Software' step. Using no online repositories (behind a work firewall with a corporate authenticator I can't use in the install environment) with the default first DVD image. And it still broke in the 'Installing Software' step."
- an on-the-metal upgrade FAILED to upgrade and has forced every service offline
- two VM installs with the xfce-cd, trying to keep systemd out failed
- a third VM install with the first full DVD, trying to keep out systemd failed
- and a fourth VM install, with the live disk image and accepting all the defaults failed.
Damn you RedHat, damn you everyone who brought systemd to light.
And damn you Debian, for going along with this - and pushing me the biggest Debian lie I've ever seen - "upgraded painlessly without forced downtime".
Call my evidence anecdotal, call it a data point in a shifting window. I call it the next day I can spare re-installing Debian 7.8.0, excluding every Jessie/Stable repository and repartitioning a 20W machine I set up over four years ago so that these upgrade stuff-ups will never necessitate me restoring from backup again.
Thanks for Wheezy, Debian. I hope against, but do believe that's going to be the last time I thank the Debian project again and hope like crazy Devuan does a good fork.